English

Unconventional orbital currents and torques due to ferro-rotational orbital textures

Materials Science 2026-02-12 v2 Mesoscale and Nanoscale Physics

Abstract

Orbital angular momentum transport has emerged as a promising route for manipulating magnetic devices, yet its generation has largely relied on the conventional orbital Hall effect. Here, we show that ferro-rotational order enables the electrical generation of unconventional orbital currents. These orbital currents represent the orbital counterparts of spin currents due to ferromagnetic order, but arise from rotation-induced symmetry breaking rather than time-reversal symmetry breaking or spin-orbit coupling. Using tight-binding models, we identify the underlying intrinsic, nonrelativistic mechanism categorized as an electric hexadecapole moment and corroborate our findings with first-principles calculations for the ferro-rotational material TiAu4_4. We further show that these rotation-induced orbital currents lead to surface orbital accumulation and unconventional orbital torque in a ferro-rotational/ferromagnetic metallic bilayer, allowing deterministic field-free switching. Our findings unveil a novel pathway for generating orbital currents beyond the conventional orbital Hall effect, broadening the landscape of orbitronics research to include novel ferroic materials and higher-order electric multipoles.

Keywords

Cite

@article{arxiv.2505.04363,
  title  = {Unconventional orbital currents and torques due to ferro-rotational orbital textures},
  author = {Daegeun Jo and Peter M. Oppeneer},
  journal= {arXiv preprint arXiv:2505.04363},
  year   = {2026}
}